We only have one goal plan, how can I assign it to new joiners throughout the year

Summary:

We only have one goal plan. It doesn't have specific goals linked to it, and was set up purely to allow employees the opportunity to create goals throughout the year, so the parameters are simply start date and end date and linked to the review year. This plan gets assigned to all employees at the beginning of the plan year but does not pick up new joiners. I want to set up a scheduled process to automatically assign this to new joiners as they join, I don't want to add one person at a time as it's